As smart phones and tablet computers are widely used, videos and other content services have developed rapidly. Downloading of large quantities of videos by using radio access technologies, especially repetitive downloading of hotspot content, consumes many network transmission resources. When a large quantity of users apply for downloading simultaneously with a service source of one hotspot content, congestion occurs on the service source, and as a result, many users cannot download the content or the downloading time is longer, especially for online videos, this may cause that a frozen picture occurs for many times during watching.
At present, in view of this, operators apply cache technologies to wireless communication systems. For example, a cache function device is placed on an RAN node to speed up UE access to web content and reduce a delay of web content access. Using a cache on an RAN node, however, requires that a storage device that stores content, for example, a hard disk, is added to the RAN node. But, there are a large number of RAN nodes, and the RAN nodes often provide limited device spaces. Therefore, it is impossible to install multiple hard disks on one RAN node to increase storage capacity. As a result, one RAN node can store only a small quantity of videos. When a UE accesses a video, and if the video is not stored in the cache of the RAN node, video access acceleration still cannot be implemented. This means that an initial play delay of video access of the UE cannot be reduced. Obviously, when more videos are stored in the cache on the RAN node, the transmission of more videos can be accelerated and user experience in using the videos will be better.
However, due to the cost for adding storage devices that store content on RAN nodes and the limited device space, the quantity of videos that can be stored in a cache on an RAN node is still limited, and therefore the effect of acceleration of video transmission that is achieved is not notable. In addition, when a UE moves to another RAN node, because a TCP connection with a source RAN node cannot be ensured, a technical problem that a video cannot be played normally results.